Metal ions are produced efficiently and selectively following photoionization from the metal-core orbital by using vacuum ultraviolet light. The purpose of the present investigation is to find the optimum condition for the efficient and selective production of the metal ions and to develop an efficient way of phorochemeical vapor deposition in the processes of semiconductor production.1. In the present investigation, it is necessary to use focused monochromatic vacuum-ultraviolet light with strong intensity. For this purpose, optics between the light source and the monochromator is of importance. Accordingly, we newly prepared a mirror system with high reflection on the basis of non-Gauusian optics and installed it in the TEPSICO-II apparatus of the BL3B beam line of the UVSOR synchrotron radiation facility in the Institute for Molecular Science. In the mirror system, the light intensity increased extremely and the efficiency of the investigation was improved.2. The metal ions and monomethyl-metal ions are produced following (n-l) d core ionization in various organometallic molecules with methyl groups. This fragmentation pattern can be explained in terms of the hybrid orbitals.3. In various organometallic molecules with methyl groups, the C ls ionization is followed by KVV Auger process and the fragmentation proceeds by way of the doubly charged parent ion. The metal-core ionization is followed by a cascade of Auger events, and the fragmentation proceeds by way of the higher multiply charged parent ions. The fragmentation patterns changes significantly depending on the site of the core electrons excited.4. The relative yield of ion pairs with aluminum ion are enhanced around the Al : 2p core ionization threshold in trimethylaluminum.